Newsletter - March 2011

 

The rule-of -thumb has been that freight comprises 70% of the cost of fertiliser on ground in New Zealand.  How accurate that figure is depends on the product and where it comes from. What is certain is that with steadily increasing oil and fuel prices the cost of imported fertiliser will also climb and may do so rapidly.
 
Nitrogen fertilisers may soon become very much more expensive and a great deal of information will need to be provided by suppliers regarding their cost effectiveness.  It is important to know the result of products provided by all fertiliser companies.
 
The environmental effect of fertilisers, and intensive pastoral farming in general, is becoming increasingly scrutinised.  The amount of nitrate leaching into ground water, not just in run-off into streams and waterways, is presently unacceptably high.
 
The water we presently have is the only water there is and no one sector of society, either urban or rural, has the right to contaminate it, and it will take time to sort all the issues. 
 
There is not and will never be one solution that fits all situations, however the interim results from the nitrate leaching trials comparing N leachate from a property using a DoloZest/CalciZest based nutrient programme to the N leachate from a property with a conventional fertiliser nitrogen driven regime is providing valuable information.
 
It is early days and a trial cannot be completed in under ten years, however the results from this work when added to all the other results over the last 8 years provides a compelling reason, in our view, for the trial to be further widened and extended.
 
Nutrient models can and do provide a great deal of useful information, however the premise that current models are accurate and correct in all respects is false.
 
Models need to allow the introduction of new information as it becomes available, and in order to achieve that, those who provide the models must be prepared to look at new information.  The refusal to accept that there may be relevant and valuable new information suggests that there is an awareness of the present model’s shortcomings.
 
The longer the refusal to examine remains in place, the speculation over the reasons why escalates, with attitudes becoming increasingly entrenched and divisive.

For us there was never a doubt that the trial work would indicate a reduction in the amount of nitrate leached, what has surprised is the size of the difference between the two properties.

 

Our position is that the increase in growth available soon after the application of fertiliser nitrogen is at the expense of soil carbon.  Nitrogen fertiliser therefore at best slows the development of humus and if too much is used there is a steady decrease in humus.

 

Humus provides storage for both water and moisture and decreasing humus steadily decreases the potential for pasture and plant growth.

 

With lessened storage, nutrient availability becomes less constant with rapid changes in plant levels occurring.  Rapidly changing plant nutrient levels mean rumens are constantly trying to adapt with consequent poor utilisation.  Poor utilisation results in trace element and mineral deficiencies becoming more prevalent with a subsequent increase in animal ill-health costs.

 

Berryman facts and figures

With physical soil structures steadily improving and plant roots developing to below 0.8m Peter felt that the farm was capable of producing 20 tonne of DM in a “good” year. 
 
We know from MAF records that 18.250 tonne has been achieved without nitrogen in the Waikato in past years however we thought 20 tonne a tall order.  
We should have known better than to question Peter’s knowledge and gut-feel based on many years of observation and farm-based trials.
 
DoloZest was first applied August 2004 and has been applied spring and autumn since.
 
This season (2010 – 2011) is the fourth season with less than 20kg/ha of fertiliser N.

With health coming in a total package it is not necessary to measure all aspects in order to know whether health is improving or declining.  In nearly all situations if one aspect is improving all aspects will be and vice versa.
 
Measuring plant or animal health takes time with each piece of information open to interpretation.
 
We have used Graham Shepherd’s locally produced but internationally recognised and accepted Visual Soil Assessment as a definitive start point.
 
From the introduction of a CalciZest/DoloZest based programme it takes 3- 5 years, typically four, for a moderately degraded pastoral soil to achieve excellence in all respects.  Improvements occur immediately after the first application with ongoing steady improvements in all aspects.
 
Ensuring there is an increase in total pasture production from Day 1 is dependant on ensuring that adequate soil nutrients, both major and minor, are available to plants at all times.  Soil tests and accurate recent nutrient input figures are important along with leaf analyses, animal blood tests, and knowledge of soil characteristics.
 
In all carefully monitored situations the following benefits have been measured

• An increase in total pasture growth over twelve months
• A more even spread of growth throughout the year
• A reduction in the need for animal health remedies
• Marked improvement in pasture persistence
• A steady increase in plant energy levels.

Management is a critical component that dictates the speed and degree to which these benefits are manifest in animal production.  Formal feed budgeting is valuable and in every district we have been able to find sound long-term data, which becomes the base to which can be added new data.
 
Feeding animals well every day provides best results and the best day to start fully feeding is today!
 
Initially we were reluctant to recommend the use of nitrogen fertiliser in conjunction with our programmes based on the concern regarding the negative affect nitrogen could have on the humus building work of the beneficial microbes and soft carbons.
 
What we now appreciate is that nitrogen fertiliser can effectively be used in conjunction with a CalciZest/DoloZest based nutrient programme without losing the unique effectiveness of the products.  The issue as we see it is finding the line between driving pasture growth and therefore dependence on nitrogen fertiliser, and using it strategically to provide growth at key times.
Autumn is perhaps the most important time of the year to manage growth.  Where pasture covers are low going into winter less growth is achievable over winter due to less leaf surface area available for energy conversion.
 
Less pasture cover means less energy available for stock and should early spring growth be hampered by less than ideal growth conditions it may take until well into October to achieve a surplus of feed.
 
On the sulphur deficient soils of the Central Plateau nitrogen fertilisers containing sulphur usually provide best performance. An application with DoloZest in autumn before soil temperatures drop markedly, and another application in mid winter to stimulate early spring growth will not noticeably negate the beneficial effect of DoloZest and CalciZest.
 
Farmers have reported strong responses from lower than normal (approx. 15kgN/ha) nitrogen application rates.  This is due to more carbon being available as an energy source due to improved carbon sequestration resulting from the application of CalciZest or DoloZest.